Telephone system.



w. w. DEAN.

TELEPHONBSYSTBM. Arrmon'lon rILnn HAY 11. 1901. RENEWED SEPT. 24, 1903.

PATENTED MAY 3, 1904.

10 MODEL.

UNITED STATES Patented May 3, 1904.

PATENT OFFICE.

WILLIAM W. DEAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCHBOARDAND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 758.623, dated May 3,1904. Application filed May 11, 1901. Renewed September Zfl, 1903.Serial No. 174,521. (No model.)

To all whom it may concern:

Be it known that I, WILLIAM \IV. DEAN, a citizen of the United States,and a resident of Chicago, county of Cook, and State of Illinois, haveinvented a new and useful Improvement in Telephone Systems, of which thefollowing is a specification.

My invention relates to telephone systems, and has for its object thesimplification of the apparatus, connections, and arrangements involved,as well as the provision of a rapid, efficient, and economical system.

It has been proposed to supply a telephoneline with alow-wound cut-offrelay and ahighwound line-relay in the line-circuit, so that when thesubscriber callsthe central station sufficient current will not flow tooperate the low-wound cut-off relay, but is ample to operate thehigh-resistanceline-relay, and when the operator plugs in in response tothe call additional current is sent through the lowwound relay tooperate it to cut out the linerelay. In such an arrangement, however, alow-wound relay is connected between one side of the talking-circuit andground or the oflice return, which might be said to be an objection, orthe marginal difference of resistance between the line-relay and thecut-off relay is so small as to tend to cause trouble. In this system,therefore, I dispense with the low-resistance relay and insert instead acutoff relay having two windings, one of said windings having,preferably, a low-resistance winding and the other preferably ahigh-resistance winding, the former being normally in the line-circuit,while the other is normally cut out or short-circuited and only throwninto the circuit when a connection is established with the line, as bythe operator in connecting for conversational purposes, whereby insteadof the low resistance in the grounded branch the full resistance of bothcoils of the relay or the high-wound coil is inserted.

The invention further consists of the novel constructions andarrangements hereinafter described, and particularly pointed out in theappended claims, reference being had to the accompanying drawings,forming a part hereof, in which the same reference characters designatelike parts throughout, and in which Figure 1 is a diagrammatic view oftwo subscribers stations and the operators connective circuit at thecentral station, and Fig. 2 is a like view showing but one battery.

In Fig. 1 the subscribers stations A and B are provided with the usualapparatus, adapted, preferably, for use with a central source ofcurrent-supply and comprising a receiver 9 and transmitter t in a bridgeof the line, that is normally open at switch-hook 4, and the bell 2 andcondenser 3 in a permanent bridge of the line. The two limbs 1 and 1 ofthe subscribers line extend to the central office, Where they areconnected with the multiple jacks 6 and with the battery B, the line 1including one armature of the cut-off relay 7 and the magnet of theline-relay 8, while the other limb, 1, includes the windings of thecut-01f relay 7 and is grounded at Cr. This relay has its Windingdivided, preferably, into a low-resistance portion 7 of a few turns andthe high-resistance portion 7 which is normally short-circuited' throughthe armature 7 3 of said relay and branch 9. The line-relay 8 is adaptedto close a local circuit through its armature and forward contact-anvil,including the individual-line lamp 10 and battery B. A ground branch 11is provided between battery B and the cut-off relay 7.

The operators connective apparatus comprises the answering and callingplugs P and O, the former having a tip-strand t and a sleeve-strand sconnected with its corresponding contacts and which are connected, bymeans of branch conductors 13 and 14 through the supervisory relays 15and 16, to the central'battery B The calling-plug O has its tip andsleeve strands t and 8 connected, respectively, with the similarsupervisory relays 17 and 18 in conductors 13 and 1A, which saidsupervisory relays are adapted to control,

through the medium of their armatures and contacts, the supervisorylamps 19 and 20, associated, respectively, with the answering andcalling plugs. The condensers c are interposed in the tip and sleevestrands to inductively join the two portions of the cord-circuit for thefree passage of the voice-currents. The ringing-key 21 is connected withthe calling-plug O, and when the operator rings a subscriber it isadapted to connect the callinggenerator 22 therewith. The operatorstelephone 23 is bridged across the cord-circuit, as shown, and includesin its circuit the condenser 24 and secondary 0f the induction-coil. Theoperators transmitter 25 is preferably charged from source B In theoperation of the system the calling subscriber takes up his receiver,thus closing the line-circuit by means of his hook-switch, and operatesthe line-relay 8 over the two limbs 1 and 1 of his line from the batteryB, said circuit also containing the low-resistance winding of thecut-off relay, the other winding, 7 thereof being short-circuited. Thislow-resistance winding 7 does not receive current enough over thiscircuit to cause it to attract its armatures, and only the line-relay isoperated to light the individual lamp 10. The operator upon observingthe signal inserts the answering-plug P into the subscribers jack and byso doing closes a local circuit, which may be traced from ground G atthe cord-circuit through the battery B conductor 1 1, supervisory relay16, sleeve-strand s of the answering-plug P, the test-ring of thesubscribers jack, and a portion of the limb 1 of the subscribers line,the low-resistance winding 7 of the cut-01f relay, and theshortcircuiting branch 9 to ground G. The closing of this circuitoperates the supervisory relay 16 and cut-01f relay 7 and causes thelatter to open the limb 1 of the telephoneline, thereby rendering theline-relay inoperative and retiring the line-signal 10. At the same timearmature 7 is attracted to open the short circuit 9 about thehigh-resistance coil 7 which coil is then inserted in said local circuitin series with coil 7' of low resistance. The current flowing, however,is sufficient maintain the same operated, while the ground or commonreturn branch is thus completed through a path of high resistance andhigh impedance. Upon learning the number of the party wanted theoperator tests the subscribers line in the usual way, and upon findingit idle inserts the calling-plug O and operates the key 21 to ring thesubscribers bell. The insertion of this plug operates cut-off relay 7,as just described,for the calling-line and line-signal 10 is preventedfrom glowing. The ringing-circuit is from ground at the generator to thesubscribers station and back and over the conductor 30 through thebattery B to ground G The continued presence of the battery upon theline when ringing prevents the deenergization of cut-off relay 7, andthe use of the branch 30 prevents rattling of the supervisory relay 18.Ten answering-plug I was first inserted, the supervisory relay 16operated, as stated, to close the circuit of lamp 19 through thearmature and front contact, while the supervisory relay 15, which isunder the control of the subscriber, was operated over the metallic lineand the tip and sleeve strands of the cord-circuit to battery B Thisserved to render the supervisory lamp 19 inert; but upon the insertionof the plug 0 the supervisory relay 17, connected with the tip-strand 25was not operated to open the circuit of the supervisory lamp 20. Thislamp, therefore, is lighted and remains so until the called subscriberresponds, when relay 17 is operated to extinguish the lamp 20. Thesubscribers are now connected for conversation. Under these conditionsthe ground or common return branch from one side of each subscribersline exists; but each includes both windings or the high-resistancewinding of the cut-off relay 7 and is therefore impervious tospeech-waves and does not hinder Ol' affect the conversation over themetallic line. WVhen the subscribers return their receivers to thetelephone-hooks, the relays 15 and 17 in the cord-circuit aredeenergized and close the circuit of the lamps 19 and 20 to indicate tothe operator that the conversation is terminated and the connection maybe pulled down and all parts restored to normal condition.

In testing the tip of the calling-plug is merely touched against thetest-rings of the jack. If a connection exists with the line, thetest-rings are connected to the live side of the battery and a click isreceived in the operators telephone. If the subscriber has just called,the test-rings are connected through line-conductor Z, the substationinstruments, and the other line-conductor, Z with the live pole of theline-battery, whereby a test-click can be received as soon as thesubscriber takes up his receiver, and there is no danger of his linebeing connected with at a multiple section before the answering operatoranswers his call.

It will be understood that the several grounds mentioned are or may bethe office return and also that the batteries mentioned may be one andthe same. The latter feature is shown in Fig. 2, wherein the samereference-characters are used as before and in which the cord-circuitstrands are connected directly with the battery B, the operation beingthe same as before described with reference to Fig. l.

Although line-relay is spoken of heroin, I consider any electromagneticsignaling device an equivalent.

While I have described the invention with particular reference to thedetails of the construction and arrangement, I would have it understoodthat the invention is not limited thereto, as many and various changesmay be made therein and still come within its scope and principle; butWhat I desire to claim by Letters Patent 1s 1. In a telephone system,the combination with a telephone-line circuit, ofaline-signalcontrolling electromagnet and a source of current in theline-circuit, acut-ofi relay having a high-resistance winding and alow-resistance winding, said low-resistance winding being normallyconnected with the line, and means to operate said cut-off relay to cutinto circuit the high-resistance winding.

2. In a telephone system, the combination with a line-circuit, of acut-off relay having two windings, a line-signal-controllingelectromagnet and a battery all included in series in said line-circuit,and means to operate the cut-off relay to render the said electromagnetinoperative.

3. In a telephone system, the combination withaline-circuit. of aline-signal-controlling electromagnet, a source of current and a cutoffrelay in said circuit, said cut-ofl relay having two windings andadapted when operated to open the circuit of said electromagnet.

L. In a telephone system, the combination with a line-circuit, of acut-01f relay having two windings, means for shunting one of saidwindings, a line-signal-controlling electromagnet and a battery, saidrelay, electromagnet and battery being in series in said linecircuit,and means to operate the cut-off relay to render the said electromagnetinoperative, substantially as described.

5. In a telephone system the combination with a telephone-line circuit,of a cut-off relay having a high-resistance winding and a lowresistancewinding, said low-resistance winding being normally connected with theline and the high-resistance winding normally cut out of the line, aline-signal-controlling electromagnet and a source of current also insaid line, and means for cutting said high-resistance winding into thecircuit when the cut-off relay is operated.

6. In a telephone system, the combination with a telephone-line, of-aline-signal-controlling electromagnet and a source of current in theline-circuit, a cut-ofl relay having a highresistance and alow-resistance winding, said low resistance winding being normallyconnected with the line, and means to operate said cut-off relay to cutout the said electromagnet and cut in the high-resistance winding.

7. In a telephone system, the combination with a telephone-line circuit,of a line-signalcontrolling electromagnet and a source of current insaid circuit, a cut-off relay having a portion only of its windingnormally in the line-circuit, and means to operate said cut-0t? relay torender the said electromagnet inoperative and to cut in the remainingportion of the cut-ofl-relay winding.

8. In a telephone system, the combination with a telephone-line circuit,of a line-signalcontrolling electromagnet and a source of current insaid circuit, a cut-off relay having two windings, only one of, which isnormally in said circuit, and means for operating said outoff relay torender the said electromagnet inoperative and to cut the other windinginto the circuit. v

9. In a telephone system, the combination with a telephone-line circuit,of a line-signalcontrolling electromagnet and a source of current in thetelephone-circuit, a cut-01f relay having a high-resistance and alow-resistance winding in said circuit, the high-resistance windingbeing normally shunted, and means to operate the cut-ofi relay to cutout the said electromagnet and break the shunt about the high-resistancewindin 10. In a telephone system, the combination with a line-circuit,of a line-signal-controlling electromagnet and a source of current insaid circuit, a cut-01f relay having a low-resistance winding and ahigh-resistance winding, the low-resistance winding being normally inthe circuit and the high-resistance winding being normally out of thecircuit, a cord-circuit, and means actuated in connecting thecord-circuit with the line to operate the cut-off relay to cut out thesaid electromagnet and to cut in the high-resistance winding of thecut-ofi relay.

11. In a telephone system, the combination with a line-circuit, of aline-signal-controlling electromagnet and a source of current in saidcircuit, a cut-off relay having a high-resistance winding and alow-resistance winding, and an armature of said relay to short-circuitits highresistance winding.

12. In a telephone system, the combination with a line-circuit, of aline-signal-controlling electromagnet and a source of current in saidcircuit, a cut off relay having two sets of switch-contacts, one of saidsets being adapted to normally short-circuit a portion of thecut-ofl-relay winding and the other to complete the line-circuit throughthe said electromagnet.

13. In a telephone system, the combination with-a line-circuit, of aline-signal-controlling electromagnet and a source of current in saidcircuit, a cut-off relay having a low-resistance and a high-resistancewinding and two sets of switch-contacts, the high-resistance windingbeing normally short circuited or shunted through one of said sets, andmeans to operate the cut-off relay in the act of making a connectionwith the line to cut out the said electromagnet and open the shortcircuit or shunt about the high-resistance winding.

14. The combination with a telephone-line, of a line-signaling deviceand a source of current in the line, a cut-ofi relay for the line havingtwo windings, one of said windings being normally short-circuited, andmeans to pass current through the other winding to operate the relay toopen the short circuit about its first-named winding and to render thesignaling. device inoperative, substantially as described.

15. The combination with a telephone-line &

of a line-signaling device, a source of current in the line, a cut-offrelay having a high-resistance and a low-resistance winding, thehighresistance winding being normally short-circuited, and means to passcurrent through the low-resistance winding to initially operate therelay to open the short circuit about its firstnamed winding and torender the signaling device inoperative, substantially as described.

16. The combination with a telephone-line, of a line-signaling deviceand a source of current in the line, a cut-off relay for the line havinga low-resistance and a high-resistance winding, the high-resistancewinding being normally shunted, and means to close the lowresistancewinding in a local circuit to operate the same to open the shunt of thehighresistance winding and to render the signal inoperative,substantially as described.

17 The combination with a telephone-line, of a line-signaling device, acut-off relay and a battery in the line, said cut-ofl' relay having alow-resistance and a high-resistance winding, the latter being normallyshunted, a jack for the line, a cord-circuit, a branch from each strandof said circuit to the opposite poles of the battery, a supervisoryrelay in the path of current over each branch, a supervisory signalcontrolled by said relays, whereby when a connection is established withthe line, the low-resistance winding of the cut-oil relay is closed in alocal circuit and is thereby operated to break the shunt about itshigh-resistance winding and to open the circuit of the signaling device,one supervisory relay being included in said local circuit to place thesupervisory signal in condition to operate, and the other supervisoryrelay being included in a circuit including the telephone-line andserving when actuated to prevent the operation of said supervisorysignal, the said battery also serving to furnish current for talkingpurposes, substantially as described.

18. The combination with a telephone-line, of a signal-controllingelectromagnet and battery in the line, a cut-off relay having twowindings, said relay being in the path of current in the line when thesubscriber is calling the central office but unresponsive thereto, andmeans for operating said relay to render said magnet inoperative,substantially as described.

19. The combination with a telephone-line, of a signal-controllingelectromagnet and battery in the line, a cut-off relay having twowindings, said relay being in the path of current in the line when thesubscriber is calling the central oflice but unresponsive thereto, andmeans for operating said relay when a connection is established with theline to operate said cut-off relay and thereby render said magnetinoperative, substantially as described.

20. The combination with a telephone-line, of a signal-controllingelectromagnet and a source of current in the line, a cut-oil relay inseries in the line and having two windings, said. relay beingunresponsive to current in the line when the subscriber is calling thecentral oflice, and means for including one of said windings in a localcircuit with a source of current when a connection is made with the lineto operate said relay and thereby render said magnet inoperative, saidlocal-current source also furnishing current for talking, substantiallyas described.

21. The combination with a telephone-line, of a signal-controllingelectromagnet and a source of current in the line, a cut-ofl' relay inseries in the line and having two windings, said relay beingunresponsive to current in the line when the subscriber is calling thecentral oifice, an operators cord-circuit, and a local circuitcontaining one winding of said relay adapted to be closed when theoperators circuit is connected with the line to operate said relay andrender said magnet inoperative, substantially as described.

22. The combination with a telephone-line, of a signal-controllingelectromagnet and a source of currentin the line, a cut-off relay inseries in the line and having two windings, said relay beingunresponsive to current in the line when the subscriber is calling thecentral ofiice, a jack for' the line, an operators circuit andconnecting-plug, and a local circuit including one winding of said relayadapted to be closed through registering contacts of the jack and plugupon the insertion of the plug into the jack in making a connection withthe line, whereby said relay is operated to render the said magnetinoperative, substantially as described.

23. The combination with a telephone-line, of a signal-controllingelectromagnet, asource of current and a cut-off relay all in series inthe line, said relay having two windings and being unresponsive tocurrent in the line when the subscriber is calling the central oflice,the limb of said line in which the said magnet is placed being normallycompleted through switch-contacts of said relay, and means for operatingsaid relay to open said contacts when the line is switched for use,substantially as described.

24 The combination with a telephone-line, of a signal-controllingelectromagnet, a source of current and a cut-off relay all in series inthe line, said relay having two windings and being unresponsive tocurrent in the line when the subscriber is calling the central office,the limb of said line in which the said magnet is placed being normallycompleted through switch-contacts of said relay, and means for directingan operative current through a winding of said relay when a connectionis established with the line, whereby to operate the same to open saidlimb and cut out said magnet, substantially as described.

25. The combination with a telephone-line, of a signal-controllingmagnet and asource of current in the line, a cutoff relay in. series inthe line having two windings and adapted when operated to render saidmagnet inoperative, and means to send current through both 1 lay beinginoperative to current in the line when a subscriber is calling thecentral oifice, and a local circuit established through saidpermanently-connected winding when a connection is made with the line todirect an operative current therethrough, substantially as described. r

27. The combination with a telephone-line, of a signal-controllingelectromagnet, and a source of current in series in the line, a cut-ofl?relay, one winding of said relay being permae nently in the path ofcurrent flowing in the line, a second winding for said relay, said relaybeing inoperative to current in the line when a subscriber is callingthe central oflice, and means for sending an operating-current throughsaid first-mentioned Winding as long as the line is switched for use,substantially as described.

28. The combination with a telephone-line, of a signal-controllingelectromagnet and a source of current in the line, a cut-off relay inseries in the line and having two windings, said relay beingunresponsive to current in the line when the subscriber is calling thecentral oflice, and means for sending an operating-current through oneof said windings over a circuit composed in part of a portion of thetalking-circuit, substantially as described.

29. The combination with a telephone-line, of a signal-controllingelectromagnet, asource of current and a cut-off relay all in series inthe line, said relay having two windings and being unresponsive tocurrent in the line when the subscriber is calling the central oflice,the limb of said line in which the said magnet is placed being normallycompleted I through switch-contacts of said relay, and a circuit closedin registering contacts of the plug and jack for sending anoperating-cur rent through one of said windings, said circuit beingcomposed in part of a portion of the talking-circuit, substantially asdescribed.

30. The combination with a telephone-line, of a signal-controllingelectromagnet, and a source of current in series in the line, a cutoffrelay, one winding of said relay being permanently in the path ofcurrent flowing in the line, a second winding for said relay, said relaybeing inoperative to current in the line when a subscriber is callingthe central oflice, and means for sending an operating-current throughsaid first winding as long as the line is switched for use and over acircuit composed in part of a portion of the talking-circuit,substantially as described.-

31. In a telephone system, the combination with a subscribers linehaving conductors normally extending to opposite poles of asource ofcurrent, of a signal-controlling electromagnet in one of saidconductors, a switch in said conductor, and a cut-off relay having twowindings, the actuating-winding thereof being connected in theother-conductor of said line and controlling said switch, substantiallyas described.

32. In a telephone system, the combination with asubscribers line havingconductors extending to opposite poles of a source of current, of asignal-controlling electromagnet in one of said conductors, a cutoffrelay having two windings, the actuating-winding thereof being in theother conductor, said relay serving to control the continuity of thefirstnamed conductor, and means to send an operative current throughsaid actuating-winding of said relay to cause it to open the oppo siteconductor when a connection is established with the line, substantiallyas described.

38. In a telephone system, the combination with a subscribers linenormally extendingto opposite poles of a source of current, ofasignal-controlling electromagnet in one of said conductors, and acut-off relay having two windings and controlling the continuity of thefirst-named conductor, said relay having its actuating-winding connectedin said opposite conductor', said winding being energized over a portionof the talking-circuit when a connection is established with the line torender the signal-controlling electromagnet inoperative, substantiallyas described.

34:. The combination with a telephone-line, of a line-signal and acut-off relay having two windings and a source of current normally incircuit in the said line, the cut-01f relay being unresponsive tocurrent from said source when the subscriber is calling, a cord-circuitadapted to be connected with the line, a su pervisory signal associatedtherewith, means for operating said signal over a local circuitincluding a portion of the talking-circuit when said cord-circuit isconnected with the line, and means controlled by the subscriber forrendering said signal inoperative by current passing over thelinecircuit, substantially as described.

35. In a telephone system, the combination with a telephoneline, of aline-signal and a source oi current in the line-circuit, a cut-off relayhaving a high-resistance winding and a with the connection-terminals,and means to having two windings,

operate said cut-ofi' relay to cut into circuit the high-resistancewinding of the same when the cord-circuit is connected with one of theconnection terminals, substantially as described.

36. The combination with a telephone-line, of a plurality ofconnection-terminals therefor permanently connected with the line, acut-off relay and a battery in the line, said cut-ofi' relay having alow-resistance winding and a high-resistance winding, the latter beingnormally shunted, a cord-circuit, a branch from each strand of saidcircuit to the opposite poles of the battery, whereby when a connectionis established with the line the lowresistance winding of the cut-offrelay is closed in a local circuit and is thereby operated to break theshunt about its high-resistance winding and to render the signalingdevice inoperative, and a supervisory signal associated with thecord-circuit and adapted to be placed in condition to operate by thecurrent in said local circuit and rendered inoperative by current fromsaid source over the telephone-line when the su bscribers telephone isin use, said source also serving to furnish current for talkingpurposes, substantially as described.

37. The combination with a telephone-line, of a signal-controllingelectromagnet and a source of current in the line, a cut-ofi' relay saidrelay being in the path of current in the line when the subscriber iscalling the central ofiice but unresponsive thereto, a jack for the linepermanently connected therewith, and a local circuit including onewinding of said relay adapted to be closed through registering contactsof the jack and plug upon insertion of the plug into the jack in makinga connection with the line, whereby said relay is operatedto render saidmagnetinoperative,substantiallyas described.

38. The combination with a telephone-line, ofa plurality ofconnecting-jacks permanently connected with the line, a cut-off relay inseries in the line and having two windings, said relay beingunresponsive to current in the line when the subscriber is calling thecentral office, a battery to furnish current for talking, and means forsending an operating-current from said battery through one of saidwindings over a circuit composed in part of a portion of thetalking-circuit when connection is established with one of saidpermanently-connected jacks, substantially described.

In witness whereof I hereunto subscribe my name in the presence of twowitnesses.

\VILLIAM W. DEAN. Witnesses:

KaMrs'rER B. MILLER, LEROY D. KELLOGG.

